The present invention is directed to a technique for limiting the range of an object sensing system, and more specifically to ensuring that certain objects detected by the sensing system that are not in the vehicle path do not cause the sensing system to provide an alarm.
Increasingly, vehicle manufactures are installing safety devices in vehicles to enable drivers to drive in a safer more efficient manner. For example, some manufactures have included forward looking systems (FLSs), rear detection systems (RDSs) and side detection systems (SDSs) within certain vehicle models. An adaptive cruise control (ACC) system is one example of a FLS.
A typical ACC system uses a radar sensor (some use laser sensors), mounted at the front of the vehicle, to detect objects in the forward path of the vehicle. If the lane ahead is clear, the ACC system maintains a set vehicle speed. However, when a slower vehicle is detected, the ACC system maintains a driver selected distance (using throttle control and limited braking) between the vehicles. A typical ACC system uses mechanically scanned radar sensors, which normally improves the ability of the system to detect targets (i.e., vehicles) in heavy traffic. A typical commercially available ACC system has a range of 150 meters, an azimuth of 15 degrees and updates at a 10 Hz rate. An ACC system generally determines a range of a detected object, as well as the relative speed of the detected object.
SDSs detect objects that are at a side of a vehicle (i.e., in a driver""s blind spot). A typical SDS includes a radar sensor that is mounted in each rear quarter panel of the vehicle. Each radar sensor is designed to detect objects in an adjacent lane. In this manner, the SDS can provide a visual indication to the driver to warn of objects in the driver""s blind spot.
An example of a RDS is a back-up aid (BUA) or a reverse sensing system. BUAs are typically used as short range parking aids and have included visual and audible alarms to warn a driver of an impending collision. A typical BUA system includes a radar sensor that provides a rear detection range of up to 6 meters. Some BUAs also include ultrasonic sensors that provide bumper coverage. A typical BUA is activated when a vehicle is put into a reverse gear and is useful for parallel parking, backing in and out of parking spaces and backing at higher speeds.
Due to the range of the sensors included within most BUAs, many objects at the rear of a vehicle cause the BUA to provide a warning of an impending contact even though an object is not within the path of the vehicle. As such, a technique that prevents certain objects that are not in the projected path of the vehicle from causing the BUA to provide an alarm is desirable.
The present invention is directed to an object sensing system that is capable of limiting its range so that certain detected objects, that are not in the path of the vehicle, do not cause the system to provide an alarm. Initially, a projected path of the vehicle is determined by using a current steering angle of the vehicle. Next, a desired warning distance is determined based upon the current steering angle. Then, a current distance to a sensed object, as derived from an object sensor, is determined. Finally, an alarm is provided only if the sensed object is within the desired warning distance.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.